Field of the Invention
The present invention relates to methods and apparatus for dehydrating natural gas and, more particularly, dehydrating natural gas in a way that minimizes or avoids the need to use external energy for the dehydration process.
Description of Related Art
Heretofore, dehydration of natural gas extracted from the ground was accomplished using a TEG (Triethylene Glycol) absorber with a glycol regeneration system. In the absorber (also known as a contact tower), TEG comes in direct contact (counter flow) with the natural gas. Water is absorbed by the TEG from the natural gas. The combination TEG and adsorbed water then enters the regeneration system (also known as a reboiler) where said combination is heated at atmospheric pressure and the water is boiled off. The TEG is then recirculated. The reboiler gives off emissions (in the form of hydrocarbons, volatile organic compounds (VOCs), and other compounds) from due to burning natural gas and from heating the combination TEG and water.
Heretofore, motor driven pumps were also used in the dehydration of natural gas extracted from the ground. These motors utilized either electrical energy from an external electrical source or some of the extracted natural gas to develop the motive power to drive the pumps for the dehydration process. In an example, natural gas or electrical powered motors were utilized to drive compressors utilized in the natural gas dehydration process.
An obvious drawback of using gas or electric powered motor(s) and a reboiler for dehydrating natural gas extracted from the ground is production of undesirable emissions such as, for example, hydrocarbons and VOCs.